scholarly journals Temperature variable high-pressure volumetric studies of diethylene glycol

2014 ◽  
Vol 70 (a1) ◽  
pp. C268-C268 ◽  
Author(s):  
Kamil Dziubek ◽  
Mohamed Mahgoub ◽  
Hesham Alsoghier ◽  
Andrzej Katrusiak
Keyword(s):  
Phase Transition ◽  
Diethylene Glycol ◽  
Volume Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Piston Cylinder ◽  
Hot Air ◽  
Phase Transition Pressure ◽  
Thermodynamic Conditions ◽  
Temperature Variable

It was demonstrated that direct compression experiments in a piston-cylinder press provide precise information on volume data and phase transition pressure complementary to X-ray diffraction. The experimental setup, described in detail previously [1], is capable of compressing liquid and solid samples up to ca. 2 GPa. We have continued these studies adding temperature control of the sample. Piston and cylinder chamber was placed in an thermally isolated mantle. The constant temperature was maintained by circulating hot air. As demonstrated by the experiments on diethylene glycol, it is a relatively quick and simple, yet efficient method for exploring phase diagrams and recording volume reduction at phase transition in different thermodynamic conditions.

scholarly journals Structural Study of δ-AlOOH Up to 29 GPa

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1055
Author(s):  
Dariia Simonova ◽  
Elena Bykova ◽  
Maxim Bykov ◽  
Takaaki Kawazoe ◽  
Arkadiy Simonov ◽  
...  
Keyword(s):  
Phase Transition ◽  
Synchrotron Radiation ◽  
Equation Of State ◽  
Room Temperature ◽  
Diamond Anvil Cell ◽  
Volume Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diamond Anvil ◽  
Murnaghan Equation

A structure and equation of the state of δ-AlOOH has been studied at room temperature, up to 29.35 GPa, by means of single crystal X-ray diffraction in a diamond anvil cell using synchrotron radiation. Above ~10 GPa, we observed a phase transition with symmetry changes from P21nm to Pnnm. Pressure-volume data were fitted with the second order Birch-Murnaghan equation of state and showed that, at the phase transition, the bulk modulus (K0) of the calculated wrt 0 pressure increases from 142(5) to 216(5) GPa.

Consolidation of Mg2Si Powder Using Shockwave Generated by Projectile Impact

2013 ◽  
Vol 767 ◽  
pp. 177-182 ◽  
Author(s):  
Hiroaki Kishimura ◽  
Yuki Yano ◽  
Hitoshi Matsumoto
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Milled Powder ◽  
Shock Pressure ◽  
Original Structure ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Shock Compaction ◽  
Phase Transition Pressure

A series of shock compaction experiments on as-received and ball-milled Mg2Si powder were conducted. The crystalline size in the shocked compacts obtained from the ball-milled powder was equivalent to that of the compacts obtained from the as-received powder. Although the shock pressure was higher than the phase transition pressure, the crystal structure reverted to its original structure under ambient conditions. For the shocked compact obtained from the ball-milled powder, a MgO peak appeared in the X-ray diffraction pattern.

scholarly journals New Phase in Fluid Hydrogen at Room Temperature

2021 ◽  
Author(s):  
Atsuko Nakayama ◽  
Yuya Isurugi ◽  
Yuya Serizawa ◽  
Satoshi Nakano ◽  
Ayako Ohmura ◽  
...  
Keyword(s):  
Phase Transition ◽  
Room Temperature ◽  
Fluid Phase ◽  
Honeycomb Lattice ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Pressure ◽  
Peak Separation ◽  
Phase Transition Pressure ◽  
New Phase

Abstract The presence of phase-transition in hydrogen (H2) at around 560 megapascal (MPa) and room temperature was clarified by Raman and x-ray diffraction studies on both pure H2 and graphite-H2 mixture. H2 is intercalated into the nano-space of graphite, which lowers the transition pressure and temporally expands the size of the honeycomb lattice of graphite under pressure up to 600 MPa. It is supposed that is caused by a gas-liquid phase-transition. According to the peak analysis for Q1(J) mode, the ortho-para conversion of H2 gradually begins to appear after the phase-transition pressure even at room temperature, while peak separation is difficult to achieve under pressure above 1.6 gigapascal (GPa) because of significant overlapping of the peak intensities. Because we have missed the ortho-para conversion which could be observed in only such a small pressure range, the fluid phase at room temperature was full of mystery.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

scholarly journals Pressure-induced Jahn-Teller Switch in the Homoleptic Hybrid Perovskite [(CH3)2NH2]Cu(HCOO)3: Orbital Reordering by Unconventional Degrees of Freedom

2021 ◽  
Author(s):  
Rebecca Scatena ◽  
Michał Andrzejewski ◽  
Roger D Johnson ◽  
Piero Macchi
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Coordination Polymer ◽  
Degrees Of Freedom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hybrid Perovskite ◽  
Jahn Teller

Through in-situ, high-pressure x-ray diffraction experiments we have shown that the homoleptic perovskite-like coordination polymer [(CH3)2NH2]Cu(HCOO)3 undergoes a pressure-induced orbital reordering phase transition above 5.20 GPa. This transition is distinct...

scholarly journals High-temperature phase transition of SrRuO3and SrHfO5: X-ray diffraction and PAC spectroscopy

1996 ◽  
Vol 52 (a1) ◽  
pp. C364-C364
Author(s):  
J. A. Guevara ◽  
S. L. Cuffini ◽  
Y. P. Mascarenhas ◽  
P. de la Presa ◽  
A. Ayala ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Temperature ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Pac Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Phase Transition
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